"The Executive must have the largely unshared duty to determine and preserve the degree of internal security necessary to exercise that power successfully. It is an awesome responsibility requiring judgment and wisdom of a high order. A very first principle of that wisdom would be an insistence upon avoiding secrecy for its own sake. For when everything is classified, then nothing is classified and the system becomes one to be disregarded by the cynical or the careless and to be manipulated by those intent on self-protection or self-promotion."

“I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description ; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it, and the motion picture involved in this case is not that.”

“I think that the court has misapplied a great constitutional principle. I cannot see how 'official religion' is established by letting those who want to say a prayer say it. On the contrary, I think that to deny the wish of these school children to join in reciting this prayer is to deny them the opportunity of sharing in the spiritual heritage of the nation.”

“Several decisions of this Court make clear that freedom of personal choice in matters of marriage and family life is one of the liberties protected by the Due Process Clause of the Fourteenth Amendment. . . . That right necessarily includes the right of a woman to decide whether or not to terminate her pregnancy.”

“Censorship reflects a society's lack of confidence in itself. It is a hallmark of an authoritarian regime.”

“In the governmental structure created by our Constitution, the Executive is endowed with enormous power in the two related areas of national defense and international relations. This power, largely unchecked by the Legislative and Judicial branches, has been pressed to the very hilt since the advent of the nuclear missile age. For better or for worse, the simple fact is that a President of the United States possesses vastly greater constitutional independence in these two vital areas of power than does, say, a prime minister of a country with a parliamentary form of government. In the absence of the governmental checks and balances present in other areas of our national life, the only effective restraint upon executive policy and power in the areas of national defense and international affairs may lie in an enlightened citizenry — in an informed and critical public opinion which alone can here protect the values of democratic government. For this reason, it is perhaps here that a press that is alert, aware, and free most vitally serves the basic purpose of the First Amendment. For, without an informed and free press, there cannot be an enlightened people.”

“The Fourth Amendment and the personal rights it secures have a long history. At the very core stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion.”